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Abstracts / Presenations

Dr. Jonathan Bennie, University of Exeter

Title: Measuring biological light pollution and uncovering its ecological effectsAbstract: Measuring biological light pollution and uncovering its ecological effects
Life on earth has evolved under predictable daily and seasonal cycles of light and darkness. The rapid spread of outdoor electric lighting across the globe over the past century has caused an unprecedented disruption to these natural light cycles. Artificial light is widespread in the environment, varying in intensity by several orders of magnitude from faint skyglow reflected from distant cities to direct illumination of urban and suburban landscapes. While our understanding of the biological effects of light on many species of plant and animals are quite well established, two major areas of uncertaintiy remain – firstly, how can we characterise the exposure of wild plants and animals to artificial light? Secondly, how do well-known physiological and behavioural responses to light impact on survival and reproduction, population dynamics, biodiversity or ecosystem processes? In the first part of this this talk I will describe how we might aim to describe the extent and nature of light pollution in biologically-relevant terms, and in the second I will describe ongoing field experiments aimed at understanding how the effects of artificial light affects not just individual animals but entire food webs.

Prof. Brian Espey, Trinity College Dublin

Title: Light Pollution in the Irish Context: both historical changes & recent dataAbstract: Using historical satellite images I will report on the growth in light at night from the whole island from pre- to post-Celtic Tiger and compare my results with changes in population and GDP, as well as the Republic's output relative to that of Northern Ireland. I will also report on ground-based measurements of sky brightness in a number of targeted areas in the Republic, including in and around Dublin, Galway, as well as rural regions such as Mayo and the Wicklow Mountains and discuss economic and environmental implications of these results..

Ms. Megan Power, Trinity College Dublin

Prof. Andrew N. Coogan, Department of Psychology, Maynooth University

Title: The Dark Side of Light-at-NightAbstract: Light has profound influences on multiple aspects of human physiology and behaviour. A key mechanism through which light exerts such effects is via modulation of the circadian timing system. This is an intrinsic biological timekeeping network that serves to impose a near twenty four hour temporal architecture on a myriad of molecular, physiological and behavioural processes. It is well established that light is the key environmental time cue (Zeitgeber) that serves to synchronise the circadian clock to external cycles, and thereby maintain the biological salience of the clock. From an anatomical perspective, the master clock of the circadian system is located to the suprachiasmatic nuclei (SCN) of the anterior hypothalamus. The SCN itself receives direct retinal innervation from a subset of intrinsically photoreceptive ganglion cells expressing the photopigment melanopsin. Light at various times of the day causes alterations in circadian timing, in a manner that it dependent on the phase of the circadian cycle during which the light is presented.

Until late into the 19th century, the presence or absence of environmental light was predominantly determined by the solar cycle. However, with the advent of electrical lighting, such environmental illumination is possible on a twenty four hour basis. This has the consequence that the circadian system may be consistently exposed to light at phases during which it would not be under natural photoperiods. This in turn may lead to chronic desynchronisation of the circadian network and adverse health outcomes. Dysfunction of the circadian system is linked to common pathologies, including cancer, diabetes and cardiovascular disease, as well as psychopathologies. Human populations who are exposed to aberrant patterns of light exposure, such as shift workers, are found to be at higher risk of developing a number of chronic conditions, and nocturnal light-induced circadian disruption is believed to be an important mechanism in heightening such risks. In this talk I will highlight mechanisms through which artificial light-at-night may impact on human health and wellbeing, and illustrate how a fundamental understanding of the circadian system may lead to measure to ameliorate such risks..